Studies On The Biology And Its Parasistic Characteristice Of Encarsia Formosa

Encarsia formosa Gahan is obligate parasitic natural enemy of greenhouse whitefly, caneffective prevention and control of greenhouse whitefly Trialeurodes vaporariorum. This studyEncarsia formosa as the research object, focus on the Host plant of Encarsia formosa parasiticeffects, this paper discusses the Encarsia formosa to different Host and Host plan of parasiticselectivity, and the extreme conditions of Encarsia formosa send Bemisia tabaco biologicalcharacteristics, such as the influence of the main results were as follows:1、 Extreme environment on Encarsia formosa parasitic Bemisia tabaci biologicalcharacteristics: Under the condition of75%relative humidity, illumination,16h, Encarsiaformosa adult life and development period decrease with the increase of temperature,26℃condition, Encarsia formosa parasitic rate and spawning quantity highest,38%and83.6respectively.Encarsia formosa from "egg-brown pupa-into a bee" in the process of development,with the increase of temperature, the insect growth through period shorten, the total developmentof23℃, the longest20.6days,35℃, the shortest was13.7days.Within the range between45%and90%relative humidity, the higher the relative humidity, Encarsia formosa life anddevelopment, the longer the duration of the longest15.8and14.2days, but the impact is not big.In26℃temperature, relative humidity75%, under the condition of light16h processingEncarsia Formosa development period was significantly shorter than14h h and18. Eclosion rateis as high as92%, but no obvious difference was found between14and18h and h,16hours oflight, temperature,26℃, relative humidity75%most conducive to Encarsia formosa grow anddevelop.2、Encarsia formosa of Trialeurodes vaporariorum and Bemisia tabaci parasitic selectivestudy: Selective experiment, by choosing coefficient, Encarsia formosa to Trialeurodesvaporariorum selection coefficient of0.6305, and Bemisia tabaci was only0.3694, shows thatwhen two nymphae exist on tomato leaf, Encarsia formosa to Trialeurodes vaporariorum parasiticnumber want to some more。Nonselective experiments, when there is separate two whitefly,Encarsia formosa parasitic rate were69.78%and41.43%respectively, explain Encarsia formosaof Bemisia tabaci and Trialeurodes vaporariorum parasitic is not affected by host competition. Forfour kinds of host plant experiment, nonselective and selective when both age4kinds of plantleaves whitefly nymphs, Encarsia Formosa of Trialeurodes vaporariorum and Bemisia tabaciparasitic choose order are all bean> tobacco> tomatoes> cucumbers, tobacco and choosing asword bean coefficient is38.70%and37.67%, respectively, show Encarsia formosa preferparasitic tobacco whitefly nymphs and string beans3、the different host plants on Encarsia formosa parasitic effect: the influence of the fivekinds of host plants of Encarsia formosa natural parasitic effects, Encarsia Formosa to Kidneybeans on Trialeurodes vaporariorum2-3instar nymphy parasitic rate is highest, at85.7%,Secondrespectively, tobacco, tomato, sunflower, cucumber in greenhouse whitefly2-3instar nymphyparasitic rate is the lowest, only30.1%. Fertility in order for the bean> tomato sunflowertobacco> tomatoes.Cucumber on Encarsia formosa development period the longest19.7d, thesecond is the sunflower is18.3d, other are about15d. Beans of Encarsia formosa developmentperiod, the shortest is only12d. Tobacco, tomato, beans three processing Encarsia formosa adultlife, more than18d, with an average of18.3d, followed by a sunflower and cucumber, with anaverage of15.9d.Largest tobacco and sunflower breeding Encarsia formosa individuals.Five kinds of host plants, small bean glandular hairs, dense, leaf area in15.250.7cm2, their averagespacing in3.2cm Encarsia formosa parasitic rate is highest, at85.7%.Followed by tobacco,tomato,78.7%and73.9%, respectively, glandular hairy thick and dense, sunflower and cucumberleaf spacing is bigger, Encarsia formosa parasitic rate is relatively low, are all below42%.Therefore, the host plant for relatively small or moderate, leaf blade glandular hairs spacingis relatively small factors, such as more appropriate Encarsia formosa parasitic, leaf size effect isrelatively weak.